If Joe Biden, 76, were elected commander in chief, he'd be 78 years old by the time he was sworn in, displacing Donald Trump as the oldest person elected president in the U.S.

The debate is already raging: Is Biden too old to run for president?

Will he have the physical and emotional energy to do the job? What if he gets sick, or worse, dies while in office?

The question of age has roiled Democratic politics since the midterms, according to a story from the Associated Press. At 78, Rep. Nancy Pelosi regained the House speaker's gavel — but only after she agreed with mostly younger lawmakers to serve in the position for no more than four years. Other potential presidential contenders, including Sens. Elizabeth Warren of Massachusetts, 69, and Bernie Sanders of Vermont, 77, and former New York Mayor Michael Bloomberg, 76, face the prospect of competing against Democrats who are decades younger.

And Biden watchers acknowledge some of his conversations with supporters revolve around his age, according to the AP.

The average retirement age in the United States is 59.8 years old. The average life expectancy for Americans is 78.7 years, which puts the U.S. far behind nations such as Spain, where the average lifespan is 85.8, and Japan, where it's 85.7.

Judith Susan Sheindlin, professionally known as Judge Judy, is a prosecution lawyer, former Manhattan family court judge, television personality, television producer and author. Her popular courtroom drama helped earn her the title of 2018's highest paid TV host.

Paul McCartney

Paul McCartney kicks off his Firefly Music Festival set with "Birthday" in 2015.(Photo: SUCHAT PEDERSON/THE NEWS JOURNAL)

Birthday: June 18, 1942

McCartney was the bass guitarist and singer for The Beatles. Today, he is a successful solo musician who recently received a Companion of Honor award from the Queen of England for his outstanding achievements in music.

Barbra Streisand

This Oct. 11, 2012 file photo shows singer Barbra Streisand performing at the Barclays Center in the Brooklyn borough of New York.

Birthday: April 24, 1942

Streisand is a singer, songwriter, actress and filmmaker who starred in "The Way We Were," "Funny Girl," "Hello, Dolly!" and more. She has sold more than 150 million albums and singles worldwide. Her newest album, released in November, is called "Walls."

Harrison Ford

Chewbacca and Han Solo (Harrison Ford) make an appearance in a trailer for "Star Wars: The Force Awakens."(Photo: NONE / StarWars.com)

Birthday: July 13, 1942

Ford is perhaps best known for playing Han Solo in the Star Wars movies and as the title character in "Indiana Jones." On Sunday at the Golden Globes, he presented the award for best director to Alfonso Cuaron for "Roma." In 2017, he starred in "Blade Runner 2049" and in 2021, he is cheduled to appear in "Indiana Jones 5."

Mitch McConnell

Reporters trail Republican Senate Majority Leader from Kentucky Mitch McConnell (C) while walking through the US Capitol after he met with US President Donald J. Trump over the budget stalemate.(Photo: JIM LO SCALZO, EPA-EFE)

Birthday: Feb. 20, 1942

McConnell is Kentucky's senior U.S. Senator and Senate Majority Leader. He is also the longest-serving U.S. Senator from Kentucky in American history. A Republican, he has tried to avoid getting involved in negotiations over an ongoing government shutdown, saying it's up to President Trump and House Democrats to strike a deal before he'll bring a funding bill to the floor.

Michael Bloomberg

Former New York City Mayor Michael Bloomberg leaves the stage after speaking to the crowd gathered at an Iowa Moms Demand Action member meeting on Tuesday, Dec. 4, 2018, at the Iowa Taproom in Des Moines. (Photo: Kelsey Kremer/The Register)

Birthday: Feb. 14, 1942

Bloomberg is the founder, CEO and owner of Bloomberg L.P., a global financial services, mass media and software company. He served as the 108th mayor of New York City for three consecutive terms beginning in 2001.

Martin Scorsese

Director Martin Scorsese acknowledges applause after receiving the 2018 Princess of Asturias Award for Arts during the Princess of Asturias Awards ceremony at the Campoamor Theatre in Oviedo, on Friday.(Photo: MIGUEL RIOPA, AFP/Getty Images)

Birthday: Nov. 17, 1942

Scorsese is an Italian-American filmmaker and historian whose career spans more than 50 years. He has directed several well-known movies, such as "GoodFellas," "Gangs of New York," "The Aviator" and "The Departed." In 2019, he is directing a movie called "The Irishman" starring Robert De Niro, who plays a labor union leader and alleged hitman for the Bufalino crime family, and Al Pacino as Jimmy Hoffa.

Klein is a fashion designer known for a range of products, including ladies' and men's apparel, denim, perfume, watches, jewelry and underwear. He has an estimated net worth of $700 million.

Jacob Zuma

Jacob Zuma is one of the most famous people named Jacob.(Photo: Phil Cole / Getty Images)

Birthday: April 12, 1942

Zuma was the fourth president of South Africa, serving from 2009 until his resignation in February 2018. Since then, he has launched a career as a recording artist and wants to preserve the country's heritage by recording the "famous struggle songs" he previously sang at political rallies. Once an apartheid hero, Zuma was recently in court facing multiple corruption charges related to a billion-dollar arms deal in the late 1990s.

Garrison Keillor

In this Sept. 30, 2014, file photo, Garrison Keillor talks with Daily Circuit host Tom Weber in the studios at Minnesota Public Radio in St. Paul. The president of Minnesota Public Radio has told employees the decision to cut business ties with former "A Prairie Home Companion" host Keillor resulted from "multiple allegations" that covered an extended period of time. Jon McTaggart held an off-the-record meeting with employees Wednesday, Dec. 6, 2017, a week after Keillor's dismissal was announced.(Photo: Jeffrey Thompson, AP)

Birthday: Aug. 7, 1942

Keillor is a voice actor and radio personality best known for creating the Minnesota Public Radio show "A Prairie Home Companion," which he hosted from 1974 to 2016. The radio station broke ties with him in 2017 over allegations of sexual misconduct.

Dick Butkus

Brian Urlacher and Dick Butkus of the Chicago Bears take the field for their game against the Philadelphia Eagles of the NFC Wild Card Playoff game at Soldier Field on January 06, 2019 in Chicago, Illinois.(Photo: Getty Images)

Birthday: Dec. 9, 1942

Butkus was a linebacker for the Chicago Bears from 1965 to 1973. He was inducted into the Pro Football Hall of Fame in 1979, and his No. 51 jersey has been retired by the Bears. He is still active in philanthropy through the Butkus Foundation, which manages various charitable causes, and on Sunday amped up Bears fans during the game against the Eagles.